FIELD OF INVENTION
The present invention relates to a programmable microcomputer or microprocessor device with associated memory designed to be operated in most circumstances through a standard telephone 12-key keypad input as augmented by four programmable function keys. The microcomputer device of the present invention, which includes the primary microprocessor operated in conjunction with other computer elements, including memory, has the overall appearance of a telephone. The primary microprocessor of the invention consists of a central processing unit and associated memory and includes enhanced integrity features.
The microcomputer device also includes standard telephone apparatus which may be operated either separately or in conjunction with the primary microprocessor. The telephone elements of the device are operated from a conventional 12-key telephone keypad through the telephone electronics of the device and perform normal telephone functions. The telephone electronics may also provide inputs through a keyboard microprocessor to the central processing unit of the primary microprocessor and its extensive memory. An additional 52-key keyboard in the QWERTY format, normally hidden in the telephone housing, provides additional inputs to the central processing unit of the primary microprocessor through the telephone electronics. Inputs to the primary microprocessor are also provided by four programmable function keys.
The primary microprocessor in conjunction with a multipurpose graphics display controller provides an output to a small cathode-ray tube display device mounted in the housing of the device for viewing by the operator. The primary microprocessor is also connected to a modem which permits the transfer of data from the primary microprocessor over the telephone line.
The 12-key telephone keypad includes a split-pill output feature which provides isolated electrical signal outputs both to the primary microprocessor and to the telephone line through a telephone dialer. The primary microprocessor has the capability of deactivating, under various conditions, the output of the telephone dialer to the telephone line so that data input by the user over the 12-key keypad does not interfere with standard telephone operations. One function key is used to change the primary microprocessor's control over the telephone from a monitoring mode to a controlling mode. The feature provides computer enhanced telephone operation before or during telephone connection to the network. The application, in response to this function key, typically provides a menu of microprocessor services, eliminates power to the telephone dialer (preventing unwanted dial tones from being transmitted to the network) and provides for transition of the telephone network to computer control.
The invention's support circuitry provides a number of integrity features. These include the following error detection or failure prevention features: (1) a determination as to whether the microprocessor software is functioning properly when the telephone is taken off-hook, (2) a watchdog timer to ensure that the computer software is not malfunctioning, (3) a parity check for the microprocessor's 512K byte volatile random access memory (RAM), (4) battery power for the microprocessor's l92K byte non-volatile RAM, (5) circuitry to provide write protection for that memory, (6) power failure detection which interrupts the microprocessor when certain voltage thresholds are crossed, (7) battery low warning and (8) independent operation of the telephone electronics from the telephone line power so that when the A/C power fails, the telephone will continue to operate.
The integrity features provide the following protections. The telephone hardware will force the telephone electronics into a manual mode when an off-hook sensor/timer senses a malfunction. A malfunction indication will appear as a service light on the telephone console. The device includes its own diagnostic elements which provide a power-on self test. An independent power failure detection element provides an indication to the primary microprocessor that it is not properly powered. Detection of power failure provides an indication to the microprocessor software that certain power limits have been crossed, permits the software to clean up and disconnect the primary microprocessor when such limits are exceeded, and permits continued use of the standard telephone features of the device. The power failure detection feature of the microprocessor provide adequate thresholds to ensure the microprocessor will run without problems through brown out conditions.
The device of this invention includes a separate microprocessor to organize keyboard inputs to the primary microprocessor. The keyboard processing unit organizes real time data to the primary microprocessor presented by either keypad, keyboard or related elements of the telephone electronics. The keyboard processing unit also includes tone detecting hardware and software which can distinguish (1) busy or fast busy, (2) call-waiting, (3) ringing and (4) dial tone and passes this information to the primary microprocessor.